Neos\Flow\Mvc\Controller\RestController::resolveActionMethodName PHP Method

    protected function resolveActionMethodName()
    {
        if ($this->request->getControllerActionName() === 'index') {
            $actionName = 'index';
            switch ($this->request->getHttpRequest()->getMethod()) {
                case 'HEAD':
                case 'GET':
                    $actionName = $this->request->hasArgument($this->resourceArgumentName) ? 'show' : 'list';
                    break;
                case 'POST':
                    $actionName = 'create';
                    break;
                case 'PUT':
                    if (!$this->request->hasArgument($this->resourceArgumentName)) {
                        $this->throwStatus(400, null, 'No resource specified');
                    }
                    $actionName = 'update';
                    break;
                case 'DELETE':
                    if (!$this->request->hasArgument($this->resourceArgumentName)) {
                        $this->throwStatus(400, null, 'No resource specified');
                    }
                    $actionName = 'delete';
                    break;
            }
            $this->request->setControllerActionName($actionName);
        }
        return parent::resolveActionMethodName();
    }